# What torque would have to be applied to a rod with a length of #7 m# and a mass of #9 kg# to change its horizontal spin by a frequency #15 Hz# over #9 s#?

##### 1 Answer

Feb 15, 2017

The torque is

#### Explanation:

The torque is the rate of change of angular momentum

The moment of inertia of a rod is

The rate of change of angular velocity is

So the torque is